1. Technical Field
The present invention relates to clutch controllers that switch a claw clutch to an engaged state.
2. Related Art
In a power train of a hybrid vehicle or the like, a claw clutch for switching a gear stage or a running mode is often incorporated (see Japanese Unexamined Patent Application Publication (JP-A) No. 2006-38136). From the viewpoint of suppressing a power loss at the time of disengagement of the clutch, it is preferable to use the claw clutch that dose not include a synchronization mechanism. However, since the claw clutch does not include the synchronization mechanism, it has been necessary to synchronize the rotation speeds of the front and the rear of the claw clutch at high accuracy in order to smoothly switch the claw clutch to an engaged state. To cope with this, in the power train described in JP-A No. 2006-38136, the rotation speeds of the front and the rear of the clutch are synchronized by using an electric motor.
However, even in a case where the rotation speeds are synchronized by using the electric motor, it is extremely difficult to cause the rotation speeds of the front and the rear of the clutch to completely match with each other, and thus a state where one of the rotation speeds exceeds the other of the rotation speeds and a state where the other of the rotation speeds exceeds the one of the rotation speeds are alternately repeated. That is, since the relative rotation direction of the front and the rear of the clutch is constantly changed, a situation in which a spline tooth is flipped and goes in and out repeatedly has occurred when the claw clutch is switched to the engaged state. The repeated going in and out of the spline tooth leads to an increase in time required to switch the claw clutch and an increase in the size of an actuator that controls the claw clutch, and hence it is desired to smoothly switch the claw clutch to the engaged state.